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/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
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package org.apache.http.impl.io;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;

import org.apache.http.annotation.NotThreadSafe;
import org.apache.http.io.BufferInfo;
import org.apache.http.io.HttpTransportMetrics;
import org.apache.http.io.SessionOutputBuffer;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.CharArrayBuffer;

/**
 * Abstract base class for session output buffers that stream data to
 * an arbitrary {@link OutputStream}. This class buffers small chunks of
 * output data in an internal byte array for optimal output performance.
 * 

* {@link #writeLine(CharArrayBuffer)} and {@link #writeLine(String)} methods * of this class use CR-LF as a line delimiter. * * @since 4.3 */ @NotThreadSafe public class SessionOutputBufferImpl implements SessionOutputBuffer, BufferInfo { private static final byte[] CRLF = new byte[] {HTTP.CR, HTTP.LF}; private final HttpTransportMetricsImpl metrics; private final ByteArrayBuffer buffer; private final int fragementSizeHint; private final CharsetEncoder encoder; private OutputStream outstream; private ByteBuffer bbuf; /** * Creates new instance of SessionOutputBufferImpl. * * @param metrics HTTP transport metrics. * @param buffersize buffer size. Must be a positive number. * @param fragementSizeHint fragment size hint defining a minimal size of a fragment * that should be written out directly to the socket bypassing the session buffer. * Value 0 disables fragment buffering. * @param charencoder charencoder to be used for encoding HTTP protocol elements. * If null simple type cast will be used for char to byte conversion. */ public SessionOutputBufferImpl( final HttpTransportMetricsImpl metrics, final int buffersize, final int fragementSizeHint, final CharsetEncoder charencoder) { super(); Args.positive(buffersize, "Buffer size"); Args.notNull(metrics, "HTTP transport metrcis"); this.metrics = metrics; this.buffer = new ByteArrayBuffer(buffersize); this.fragementSizeHint = fragementSizeHint >= 0 ? fragementSizeHint : 0; this.encoder = charencoder; } public SessionOutputBufferImpl( final HttpTransportMetricsImpl metrics, final int buffersize) { this(metrics, buffersize, buffersize, null); } public void bind(final OutputStream outstream) { this.outstream = outstream; } public boolean isBound() { return this.outstream != null; } public int capacity() { return this.buffer.capacity(); } public int length() { return this.buffer.length(); } public int available() { return capacity() - length(); } private void streamWrite(final byte[] b, final int off, final int len) throws IOException { Asserts.notNull(outstream, "Output stream"); this.outstream.write(b, off, len); } private void flushStream() throws IOException { if (this.outstream != null) { this.outstream.flush(); } } private void flushBuffer() throws IOException { final int len = this.buffer.length(); if (len > 0) { streamWrite(this.buffer.buffer(), 0, len); this.buffer.clear(); this.metrics.incrementBytesTransferred(len); } } public void flush() throws IOException { flushBuffer(); flushStream(); } public void write(final byte[] b, final int off, final int len) throws IOException { if (b == null) { return; } // Do not want to buffer large-ish chunks // if the byte array is larger then MIN_CHUNK_LIMIT // write it directly to the output stream if (len > this.fragementSizeHint || len > this.buffer.capacity()) { // flush the buffer flushBuffer(); // write directly to the out stream streamWrite(b, off, len); this.metrics.incrementBytesTransferred(len); } else { // Do not let the buffer grow unnecessarily final int freecapacity = this.buffer.capacity() - this.buffer.length(); if (len > freecapacity) { // flush the buffer flushBuffer(); } // buffer this.buffer.append(b, off, len); } } public void write(final byte[] b) throws IOException { if (b == null) { return; } write(b, 0, b.length); } public void write(final int b) throws IOException { if (this.fragementSizeHint > 0) { if (this.buffer.isFull()) { flushBuffer(); } this.buffer.append(b); } else { flushBuffer(); this.outstream.write(b); } } /** * Writes characters from the specified string followed by a line delimiter * to this session buffer. *

* This method uses CR-LF as a line delimiter. * * @param s the line. * @exception IOException if an I/O error occurs. */ public void writeLine(final String s) throws IOException { if (s == null) { return; } if (s.length() > 0) { if (this.encoder == null) { for (int i = 0; i < s.length(); i++) { write(s.charAt(i)); } } else { final CharBuffer cbuf = CharBuffer.wrap(s); writeEncoded(cbuf); } } write(CRLF); } /** * Writes characters from the specified char array followed by a line * delimiter to this session buffer. *

* This method uses CR-LF as a line delimiter. * * @param charbuffer the buffer containing chars of the line. * @exception IOException if an I/O error occurs. */ public void writeLine(final CharArrayBuffer charbuffer) throws IOException { if (charbuffer == null) { return; } if (this.encoder == null) { int off = 0; int remaining = charbuffer.length(); while (remaining > 0) { int chunk = this.buffer.capacity() - this.buffer.length(); chunk = Math.min(chunk, remaining); if (chunk > 0) { this.buffer.append(charbuffer, off, chunk); } if (this.buffer.isFull()) { flushBuffer(); } off += chunk; remaining -= chunk; } } else { final CharBuffer cbuf = CharBuffer.wrap(charbuffer.buffer(), 0, charbuffer.length()); writeEncoded(cbuf); } write(CRLF); } private void writeEncoded(final CharBuffer cbuf) throws IOException { if (!cbuf.hasRemaining()) { return; } if (this.bbuf == null) { this.bbuf = ByteBuffer.allocate(1024); } this.encoder.reset(); while (cbuf.hasRemaining()) { final CoderResult result = this.encoder.encode(cbuf, this.bbuf, true); handleEncodingResult(result); } final CoderResult result = this.encoder.flush(this.bbuf); handleEncodingResult(result); this.bbuf.clear(); } private void handleEncodingResult(final CoderResult result) throws IOException { if (result.isError()) { result.throwException(); } this.bbuf.flip(); while (this.bbuf.hasRemaining()) { write(this.bbuf.get()); } this.bbuf.compact(); } public HttpTransportMetrics getMetrics() { return this.metrics; } }





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